self-sacrificer

noun2

1. •
   A person who is self-sacrificing, who sacrifices their own benefit for the good of another or others.

   • It was a state of joy which only the self-sacrificer knows. — 1906
2. •
   A person who offers himself or herself as a sacrifice (as a religious act, for example).

   • […] they even willingly forfeit all the rest, and turn as it were Martyrs and Self-sacrificers to but so faint a Shadow or scant Resemblance of the first uncreated Perfection […] — 1668